Recently, the HDMI (High Definition Multimedia Interface) has been spread widely as a communication interface that transmits a digital video signal and a digital audio signal that accompanies the video signal at a high speed from, for example, a DVD (Digital Versatile Disc) recorder, a set top box, or another AV source (Audio Visual source) to a television receiver, a projector, or another display. For example, Patent Document 1 includes a detailed description of the HDMI standard.
Also, recently, adoption of CEC (Consumer Electronics Control) that can control an electronic device connected to a television receiver by using a remote control sender of the television receiver has been actively done. This is a scheme that adds a CEC control signal line to an HDMI signal.
FIG. 24 illustrates a structure example of a known AV system 200. The AV (Audio Visual) system 200 includes a disc recorder 210 serving as a source device, a photo player 370 serving as a source device, and a television receiver 250 serving as a sink device.
The photo player 370 and the television receiver 250 are connected to each other via an HDMI cable 391. That is, one of two ends of the HDMI cable 391 is connected to an HDMI terminal 371 of the photo player 370, and the other end is connected to an HDMI terminal 251 of the television receiver 250.
The disc recorder 210 and the television receiver 250 are connected to each other via an HDMI cable 392. That is, one of two ends of the HDMI cable 392 is connected to an HDMI terminal 211 of the disc recorder 210, and the other end is connected to an HDMI terminal 254 of the television receiver 250.
The television receiver 250 is a CEC-compliant device and includes an infrared receiving unit (IR receiving unit) 276 that receives an infrared remote control signal from a remote control sender 277. Also, the disc recorder 210 and the photo player 370 are CEC-compliant devices.
In the AV system 200 illustrated in FIG. 24, both the disc recorder 210 and the photo player 370 are CEC-compliant devices. Therefore, the operation of the disc recorder 210 and the photo player 370 can be controlled using the remote control sender 277 of the television receiver 250.
FIG. 25 illustrates an example of an operation sequence at the time the photo player 370 and the disc recorder 210 are connected to the television receiver 250.
(a) When the photo player 370 is connected to the television receiver 250 via the HDMI cable 391, (b) the photo player 370 obtains a Physical Address [1000] from the television receiver 250 by using an HDMI control protocol.
A CEC-compliant device is defined to obtain a Logical Address at the time of an HDMI connection. Using the logical address, the CEC-compliant device sends/receives a message. FIG. 26 illustrates a CEC table that illustrates the corresponding relationship between a device and a CEC logical address.
A device called “TV” is a television, a projector, or the like. A device called “Recording Device” is an HDD recorder or the like. A device called “Tuner” is an STB (Set Top Box) or the like. A device called “Playback Device” is a DVD player, a camcorder, or the like. A device called “Audio System” is an AV amplifier or the like.
As is clear from the table of FIG. 26, the number of individual devices that can be connected at a time is defined. When devices greater than or equal to the defined number are connected, logical addresses of these devices will be {15}.
Referring back to FIG. 25, (c) since the photo player 370 itself is a playback device, the photo player 370 decides the logical address {4} as a CEC-controlled Playback Device on the basis of the table of FIG. 26. In this case, after the photo player 370 recognizes that there is no other device that has the logical address {4} by performing Polling Message using the CEC control protocol, the photo player 370 decides the logical address {4} as its logical address.
(d) After the photo player 370 decides the logical address {4} as described above, the photo player 370 notifies the television receiver 250 of the fact that the physical address [1000] is a CEC-compliant device {4} by performing Report Physical Address using the CEC control protocol.
(e) When the disc recorder 210 is connected to the television receiver 250 via the HDMI cable 392, (f) the disc recorder 210 obtains a Physical Address [2000] from the television receiver 250 by using the HDMI control protocol.
(g) Since the disc recorder 210 itself is a recording device, the disc recorder 210 decides the logical address {1} as a CEC-controlled Recording Device on the basis of the table of FIG. 26. In this case, after the disc recorder 210 recognizes that there is no other device that has the logical address {1} by performing Polling Message using the CEC control protocol, the disc recorder 210 decides the logical address {1} as its logical address.
(h) After the disc recorder 210 decides the logical address {1} as described above, the disc recorder 210 notifies the television receiver 250 of the fact that the physical address [2000] is a CEC-compliant device {1} by performing Report Physical Address using the CEC control protocol.
FIG. 27 illustrates an example of an operation sequence at the time playback control of the photo player 370 and the disc recorder 210 is performed by using the remote control sender 277 of the television receiver 250.
(a) When a user switches the input to the photo player 370 by using the remote control sender 277 of the television receiver 250, (b) the television receiver 250 notifies a connected CEC-compliant device(s) of the fact that the input has been switched from the television receiver 250 to the photo player 370 by performing SetStreamPath[0000]→[1000] using the CEC control protocol.
(c) The photo player 370 with the logical address [1000] detects this notification and notifies the connected CEC-compliant device(s) of the fact that the device under control of CEC has been switched to the photo player 370 by performing ActiveSource{4}→{F}. (d) Accordingly, the television receiver 250 switches a remote control sending destination to the photo player 370.
(e) When the user presses a playback key on the remote control sender 277 of the television receiver 250, (f) the television receiver 250 notifies the connected CEC-compliant device(s) of UserControlPressed:PB{4} using the CEC control protocol. (g) The photo player 370 with the logical address {4} detects this notification, plays an image in a flash memory, and sends the playback output to the television receiver 250 via the HDMI cable 391.
Next, (h) when the user switches the input to the disc recorder 210 by using the remote control sender 277 of the television receiver 250, (i) the television receiver 250 notifies the connected CEC-compliant device(s) of the fact that the input has been switched from the photo player 370 to the disc recorder 210 by performing SetStreamPath[1000]→[2000] using the CEC control protocol.
(j) The disc recorder 210 with the logical address [2000] detects this notification and notifies the connected CEC-compliant device(s) of the fact that the device under control of CEC has been switched to the disc recorder 210 by performing ActiveSource{1}→{F}. (k) Accordingly, the television receiver 250 switches the remote control sending destination to the disc recorder 210.
(m) When the user presses the playback key on the remote control sender 277 of the television receiver 250, (n) the television receiver 250 notifies the connected CEC-compliant device(s) of UserControlPressed:PB{1} using the CEC control protocol. (p) The disc recorder 210 with the logical address {1} detects this notification, plays an image recorded on a disc, and sends the playback output to the television receiver 250 via the HDMI cable 392.
FIG. 28 illustrates a structure example of the photo player 370. The photo player 370 includes the HDMI terminal 371, an HDMI sending unit 372, a CPU (Central Processing Unit) 374, a ROM (Read Only Memory) 375, a RAM (Random Access Memory) 376, a bus 377, an external memory interface 378, and a signal processing LSI 379.
In the photo player 370, the CPU 374, the ROM 375, and the RAM 376 are interconnected by the bus 377. The CPU 374 controls the operation of each unit of the photo player 370. The ROM 375 stores an operating program of the CPU 374 and the like. The RAM 375 is used as a work area for the CPU 374 or the like. The CPU 374 executes a control operation by reading the operating program from the ROM and expanding the operating program on the RAM.
Furthermore, the external memory interface 378 and the signal processing LSI 379 are connected to the bus 377. The external memory interface 378 includes a loading unit for a flash memory 380. Under control of the CPU 374, the external memory interface 378 reads still image data from the loaded flash memory 380. For example, the external memory interface 378 is a memory card drive, and the flash memory 380 is a memory card.
As described above, still image data read from the flash memory 380 is compressed and encoded data such as JPEG data. The signal processing LSI 379 applies expansion processing to the still image data read from the flash memory 380 and obtains a baseband video signal (image data). The HDMI sending unit 372 sends the baseband video signal, which is obtained by the signal processing LSI, from the HDMI terminal 371 by performing HDMI-based communication.
In the photo player 370 illustrated in FIG. 28, a CEC control command supplied from the television receiver 250 via a CEC line of the HDMI cable 391 is, as indicated by broken lines in FIG. 29, supplied from the HDMI sending unit 372 via the CPU 374 to the RAM 376, and temporarily held in the RAM 376. The CPU 374 reads and analyzes the CEC control command held in the RAM 376.
When the CEC control command is a playback command, reading of still image data from the loaded flash memory 380 is performed using the external memory interface 378 under control of the CPU 374. The still image data read from the flash memory 380 is, as indicated by a broken line in FIG. 30, supplied from the external memory interface 378 via the bus 377 to the RAM 376, and temporarily held in the RAM 376.
Thereafter, the still image data held in the RAM 376 is, as indicated by a broken line in FIG. 30, read from the RAM 376 and supplied to the signal processing LSI 379. The signal processing LSI 379 applies expansion processing to the still image data supplied from the RAM 376 and obtains a baseband video signal (image data). The baseband video signal is supplied to the HDMI sending unit 372, and sent to the HDMI cable 391 connected to the HDMI terminal 371.
As described above, since both the disc recorder 210 and the photo player 370 in the AV system 200 illustrated in FIG. 24 are CEC-compliant devices, the operation of the disc recorder 210 and the photo player 370 can be controlled using the remote control sender 277 of the television receiver 250.
In contrast, an AV system 200A illustrated in FIG. 31 is also conceivable. In FIG. 31, portions corresponding to FIG. 24 are given the same reference numerals. In the AV system 200A, instead of the disc recorder 210 in the AV system 200 illustrated in FIG. 24, a disc recorder 210A is connected via the HDMI cable 392 to the television receiver 250.
The disc recorder 210A is a CEC-non-compliant device. Therefore, when the disc recorder 210A is connected to the television receiver 250 via the HDMI cable 392, the disc recorder 210A obtains a Physical Address [2000] from the television receiver 250 using the HDMI control protocol, but does not obtain a CEC logical address.
Since the photo player 370 is a CEC-compliant device in the AV system 200A, the operation of the photo player 370 can be controlled using the remote control sender 277 of the television receiver 250. However, since the disc recorder 210A is a CEC-non-compliant device, the operation of the disc recorder 210A cannot be controlled using the remote control sender 277 of the television receiver 250.
Therefore, the operation of the disc recorder 210A in the AV system 200A is performed using a remote control sender 232 of the disc recorder 210A by using an infrared receiving unit 231 included in the disc recorder 210A.    Patent Document 1: Publication No. WO2002/078336